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Author Topic: Microcosm Shovelhead R31 engine  (Read 4536 times)

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Re: Microcosm Shovelhead R31 engine
« Reply #15 on: April 01, 2023, 05:41:41 am »
Quote from: gamma13r on April 01, 2023, 01:40:03 am
engine-man,

I contacted Jin on EBay, and asked him about the cam. He said it costs $22 with included shipping. He sent me his PP info and I bought one, and also sent him some extra $ bc he said he will draw me out a cam / flywheel / magnetic trigger timing diagram for the shovel.  Hope he’s able to draw it for me soon… know he’s really busy.  Soon as he sends me the diagram I’ll send it to you on FB messenger 🤙


Sounds awesome ! I hope he replies to me too.
Sharing the diagram would be really appreciated  ;D
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Re: Microcosm Shovelhead R31 engine
« Reply #16 on: April 02, 2023, 07:11:40 pm »
Hey engine-man, I just sent you a message on Facebook messenger, Mr. Jin got back to me.  I sent you a picture of the diagram he sent me.

Once you get your shovel timed, I need your help in the correct magnetic gear position in relation to the crank being at bottom dead center.

Talk soon man,  Jon Cook
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Re: Microcosm Shovelhead R31 engine
« Reply #17 on: April 05, 2023, 12:09:53 am »
It's will be interesting to see if the new camshaft will sort the problem. The left cylinder ( opposite fuel tank ) simply doesn't want to work. I noticed it is sucking air through the exhaust pipe. Properly an issue with valves and the timing of the camshaft.
It's hard to properly diagnose it without seeing the valve rockers in action unlike other harley engines made. I made it to the point that engine was properly sucking fuel from the carb and managed to run couple of times for 10-15 seconds then died.

If someone else has this engine, it would be good to share your experience and perhaps issues
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Re: Microcosm Shovelhead R31 engine
« Reply #18 on: April 08, 2023, 07:18:51 pm »
Hi guys, I’m new here and I have the shovel head engine. And as you say when you take the cam cover off the cam comes out with it . No timing marks. I’ve been trying to get a hold of Jim for a while and no reply. You say he has an updated cam and you have the valve timing diagram? Wow! Could you help me please? It would be greatly appreciated! Thanks 😊
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Re: Microcosm Shovelhead R31 engine
« Reply #19 on: April 09, 2023, 01:33:38 am »
Quote from: Vbiker on April 08, 2023, 07:18:51 pm
Hi guys, I’m new here and I have the shovel head engine. And as you say when you take the cam cover off the cam comes out with it . No timing marks. I’ve been trying to get a hold of Jim for a while and no reply. You say he has an updated cam and you have the valve timing diagram? Wow! Could you help me please? It would be greatly appreciated! Thanks 😊


Hey vbiker 👋

It happens dude.. After having issues w’ my R31, I got ahold of Jin and asked him about the cam / flywheel timing.  Here is a diagram Jin sent me that will help

Position the grub screw on the flywheel straight down, then install the camshaft with the 2nd cam lobe pointing straight down


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Re: Microcosm Shovelhead R31 engine
« Reply #20 on: April 09, 2023, 01:52:02 am »

vbiker,

I forgot to mention the updated camshaft;
I ordered mine from Jin directly, it costs $22 including shipping. Jim said the updated cam is supposed have a lower idle and better running characteristics.
Looking forward to when mine arrives
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Re: Microcosm Shovelhead R31 engine
« Reply #21 on: April 09, 2023, 11:01:23 am »
Hi Gamma13r,OMG! Thank you so much for the diagram!! Let me know how the new cam works out. The cam lobes in my engine are sad looking. I’ve tried to contact Jin through eBay twice and haven’t got an answer. Any secret to getting him to respond? Again thank you for the diagram!
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Re: Microcosm Shovelhead R31 engine
« Reply #22 on: April 09, 2023, 07:03:05 pm »
Quote from: Vbiker on April 09, 2023, 11:01:23 am
Hi Gamma13r,OMG! Thank you so much for the diagram!! Let me know how the new cam works out. The cam lobes in my engine are sad looking. I’ve tried to contact Jin through eBay twice and haven’t got an answer. Any secret to getting him to respond? Again thank you for the diagram!

Of course & no problem!

Sometimes getting a hold of Jin can be tricky, but I know it’s bc he’s so busy… Here’s what I have done - if he doesn’t get a hold of you in a few days after you sent your message on eBay, sent him another message on eBay and just ask if he could contact you back.  -here’s what I think also happens: eBay has a bot that scans messages for people looking to buy goods from sellers outside of eBay; and they delete messages that even remotely sound like any purchase. sometimes I think that my messages haven’t gotten to Jim,  bc eBay has deleted them. 

Jin is a really good dude and he will get back to you, just takes a bit sometimes.
How he develops so many different miniature engines is beyond me.

As soon as my camshaft arrives, I will report back and let you all know the changes. I’m sure it will help a lot. I own an R29 Knucklehead, and it loves to run…and run extremely well. 
I have probably put at least 35 hours on it, since I got it last November.  It’s always a “one flip wonder” - idles and revs beautifully, no oil splooge & no smoke.  I have a lot of confidence in the R31 shovelhead, it just needs some tweaks and tuning.

I run all of my miniature engines on Coleman camping fuel and marvel mystery oil @ around 45:1, and I run my engines a lot… all of my engines seem to love it.

I’m “ 133mhz “ on YouTube 🤙

Hope this helps dude - as soon as I get my Camshaft I’ll report back


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Re: Microcosm Shovelhead R31 engine
« Reply #23 on: April 10, 2023, 08:08:08 am »
Thanks for the advice. I own an R29 Knucklehead as well. I call it my star pupil as it starts easily and runs well…lol.

I got the Shovelhead running with your help. I’m going to convert to the fuel mix that you’re using. I’ve tried Zippo mix, different gasoline mix’s. The engines Seem to idle nicely but don’t rev the way they should. I’ve tried adjusting the carburetor but doesn’t seem to help.

Again thanks for your advice!
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Re: Microcosm Shovelhead R31 engine
« Reply #24 on: April 10, 2023, 10:29:21 am »
That’s awesome man!  Glad to hear you got your R31 running 🤙
Definitely try Coleman camping fuel & marvel mystery oil; it works great… and my gf doesn’t mind too much when I start my engines in the house 😂
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Re: Microcosm Shovelhead R31 engine
« Reply #25 on: April 10, 2023, 11:31:44 am »
Lol… I run mine in the house too. Have to open the door and air it out sometimes 😊
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Re: Microcosm Shovelhead R31 engine
« Reply #26 on: April 10, 2023, 04:03:13 pm »
Hi, I just tried the Coleman fuel and Marvel Mystery oil mix and works great. Thanks for another good piece of advice. Doesn’t stink the house up as bad 😂
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Re: Microcosm Shovelhead R31 engine
« Reply #27 on: April 10, 2023, 08:42:01 pm »
Quote from: Vbiker on April 10, 2023, 04:03:13 pm
Hi, I just tried the Coleman fuel and Marvel Mystery oil mix and works great. Thanks for another good piece of advice. Doesn’t stink the house up as bad 😂

Haaa you’re welcome dude, yeah… once you go to Coleman fuel and MMO, you’ll never go back.  Clean burning, virtually no carbon deposits or smoke..  I love it. The MMO is also great on the O-rings… it prevents swelling unlike some 2 stroke oils.

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Re: Microcosm Shovelhead R31 engine
« Reply #28 on: April 10, 2023, 09:44:24 pm »
I sent a message to Jin asking him to reply and he did. I told him I heard you had an updated camshaft for the R31. So waiting on a response.

You’re the man! You’ve given me nothing but good advice! The engines love the new fuel mix.

Have you noticed the floating wrist pins have no retainer so the pin comes out and scores the cylinder wall? Just wondering what your fix is for this bugga boo.
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Re: Microcosm Shovelhead R31 engine
« Reply #29 on: April 10, 2023, 10:15:57 pm »
Quote from: Vbiker on April 10, 2023, 09:44:24 pm
I sent a message to Jin asking him to reply and he did. I told him I heard you had an updated camshaft for the R31. So waiting on a response.

You’re the man! You’ve given me nothing but good advice! The engines love the new fuel mix.

Have you noticed the floating wrist pins have no retainer so the pin comes out and scores the cylinder wall? Just wondering what your fix is for this bugga boo.


That’s awesome man!   Yep, I’ve noticed the floating wrist pins, but haven’t yet done anything just yet… glad you reminded me. 

My plan is to get an extremely thin sheet of Teflon or ptfe, and use a small leather punch to punch out some tiny discs I can use on each side of the piston pin.  I know someone on the forum has done something similar on their H74 or H75.   

I’d planned on doing this for my Knucklehead once it needed the o rings replaced, but since using MMO the o rings definitely don’t need to be replaced… if anything the compression is much stronger than when it was new.  And I’ve put a lot of hours on my little knucklehead
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